Grinding machine table operating mechanism



March 6, 1934. c FLYGARE 1,949,511

GRINDING MACHINE TABLE OPERATING MECHANISM Filed Dec. 31, 1928 W 556 5Car/ gar? Patented Mar. 6, 1934 UNITED STATES PATENT! OFFICE Carl G.Flygare, Worcester, Mass., assignor to Norton Company, Worcester, Mass.,a. corporation of Massachusetts Application December 31, 1928, SerialNo. 329,458

11 Claims.

This invention relates to grinding machines and more particularly to amechanism for operating a grinding machine table and controlling thespeed thereof.

In grinding many types of work, and particularly with a wide wheel feddirectly and continuously into the work, it is often desirable to movethe wheel first rapidly towards the work and then at a slower rate togrind the work and perhaps at a still slower speed to finish grind it,or to stop the wheel movement altogether. For rapid production methodsthe wheel feed should be substantially automatically controlled and thechanges in its speed should take place when the wheel has reachedcertain definite locations. For example, in grinding crankshafts andother similar objects in which not only the cylindrical portion of thecrankpin but also the cheeks and fillets adjacent the end of thecrankpin are 20 ground, it is necessary to move the grinding wheelthrough a considerable distance to position it in proper relation withthe object to be ground and also to remove it therefrom to aninoperative position. In grinding the pin, it is desirable that thegrinding wheel be fed as rapidly as possible during the idle movement ofthe wheel and then to have a slower feeding movement to grind the cheeksand the fillets of the pin and a still slower speed to grind thecylindrical portion or body of the pin and a final stopping of the feedor a removal of the grinding wheel when the work has been reduced to therequired size.

It is accordingly one object to provide a grinding machine tableoperating mechanism which is capable of moving the table in a steppedseries of uniform speeds.

It is another object of this invention to provide a simplified controlfor a slidable grinding machine table which is so arranged that when thetable has reached a predetermined position .it automatically actuates amechanism to cause a different but uniform speed thereafter.

It is another object of this invention to provide a fluid pressuremechanism for moving a table which is arranged so that the movement ofthe table actuates a throttling device in the fluid pressure system,when the table has reached a predetermined position, to change the speedof the table to a slower but uniform rate.

It is still another object of this invention to provide a fluid pressureoperating mechanism for a grinding wheel slide which permits a rapidwithdrawal and a rapid approach of the grinding wheel into a positionadjacent to the surface of the work and is so arranged that the movementof the wheel slide operates automatically, when the slide has reached apredetermined position, to actuate a throttling device in the fluidpressure system and slow down the movement of the 50 wheel slides to adifferent but uniform speed.

The drawing illustrates one embodiment of the invention as applied to agrinding wheel feed mechanism which is operated hydraulically in thesedrawings in which like reference nu merals indicate like parts:

Fig. 1 is a fragmentary perspective view partly broken away and partlyin section to illustrate the relation of the hydraulic mechanism to a qgrinding machine wheel slide; m

Fig. 2 is a longitudinal sectional view through the reversing valvewhich controls the direction of flow of fluid to the system and showingthe valve piston in position to admit fluid to move the wheel sliderearwardly to an inoperative posltion;

Fig. 3 is a longitudinal horizontal section through the throttle valvehaving the valve stem broken away to show the v-port;

Fig. 4 is a fragmentary sectional view partly broken away showing theconnections between the fluid pressure. piston and cylinder and thethrottle valve;

I Fig. 5 is a similar fragmentary view with the fluid pressure pistonand cylinder removed and @5 the first trigger released and the throttlevalve moved to its second position; and

Fig. 6 is a sectional view through one of the stop members on anenlarged scale showing the construction and adjustment of the same.

In accordance with the invention, and as illustrated in the drawing, agrinding'machine may comprise a grinding wheel 11 rotatably mounted on awheel slide 12 which is slidably supported on the V-way l3 and flat way14 on the base of the 95 machine. The work piece 16 shown as'a fragmentof a crankshaft may bemounted on any of the well-known work supportingand rotating devices in an operative relation to the wheel. The mm wheelslide 12 is moved'toward and from the work piece by a feeding mechanismwhich is preferably so arranged that the grinding wheel will be given arapid approaching movement to bring it into a position adjacent to thesurface of the work, and then it will be slowed down to a definite andpredetermined speed for rough grinding of the work. This speed continuesuntil the wheel has reduced the work to a given size; then the mechanism0perates to reduce the feed to a still slower but uniform rate to finishgrind the piece of work.

In the preferred construction, this mechanism may comprise afluid-pressure system such as a cylinder 20, which is preferably fixedtothe base of the machine and. a piston 21 which is'slidably mountedtherein. The piston 21 is connected to one end of the piston rod 22which is in turn connected to the wheel slide 12 by a bracket 23depending therefrom. Fluid under pressure may be admitted to either endof the cylinder 20 to control the movement of the grinding wheel towardor from the work, and this fluid may be obtained from any suitablesource of supply, such as a 1 arranged that the operator may manuallycontrol the direction of movement of the grinding wheel. To accomplishthis, a reversing valve 25 is provided. This valve is preferably of thebalanced piston type having the pistons 26 and 2'? slidably mountedwithin the valve casing 25 on a valve stem 28. Fluid under pressure isadmitted through the inlet pipe 30 to the valve chamber 31 and throughthe pipe 32 to the cylinder chamber 33 to force the piston 21 toward theleft, as viewed in Fig. l, to feed the grinding wheel toward the work.Fig. 1 shows the parts arranged for starting the forward feedingmovement of the wheel.

In accordance with this invention, the fluid pressure system includes athrottling device arranged to control the fluid flow, and this device isactuated in timed relation with the wheel feeding movement, andpreferably by direct connectionswith the wheel slide, so that when thewheel has reached a predetermined position in its forward movement, thefluid flow is throttled to give a different but slower rate of uniformmovement. This throttling device may comprise a valve 35 having thepistons 36 and 37 mounted on a valve stem 38 and arranged in the systemto control" the exhaust of fluid from the chamber 34 of the wheel slidedriving mechanism. When the piston 21 moves toward the lift, as viewedin Fig. 1, the

fluid in the chamber 34 is forced outwardly through the pipe 39 into thevalve chamber 40 in the valve 25. The fluid entering the chamber 40 isthen forced through pipe 41 and the V- shaped port 42 into the valvechamber 43 and then outwardly through the exhaust port 44 and theexhaust pipe 45 back to a pump or reservoir from which the flud supplyis obtained. This V- port, as shown in Figs. 1 and 3, tapers towards theright (Fig. 1) so that when the piston 36 moves towards the right(Fig. 1) it gradually closes the port. The V-shape of the port permits afine regulation of the wheel feed at the slower speeds. It will be notedthat the V-shaped port is countersunk in the wall of the valve chamber,so that the fluid may have full access to the pipe 41. It will bereadily seen from this construction, that the rate of movement of thegrinding wheel slide may be readily controlled by properly positioningthe valve piston 36 relative to the V-port 42 and so controlling theexhaust of fluid from the cylinder chamber 34 and consequently the rateof movement of the grinding wheel toward the work.

The valve 25 is arranged to control the direction of flow of fluidthrough the system and is preferably controlled by a manually operablelever pivotally mounted on a stud 51 on the'base of the machine. Thelever 50 has a short arm 52 which is connected by a pin 53 to the yokedmember 54 on the outer end of the valve 6 3.- By

swinging the lever 50, the positions of the valve pistons 26 and 27 maybe readily changed, when it is desired to reverse the direction of flowof fluid to move the griding wheel towards or from the work. To stop theinfeed of the grinding wheel, the lever 50 is shifted into a position50a (Fig. 1) thereby moving the valve pistons 26 and 2'7 into positions26a and 27a, as shown in dotted lines in Fig. 2. In this position of theparts, the valve piston 26 covers the port leading to the pipe 39 whichleads to the cylinder chamber 34 and the piston 27 in position 27acovers the port leading to the pipe 32 which leads to the cylinderchamber 33 thereby preventing fluid under pressure from entering eitherside of the piston 21, and so stopping the movement of the grindingwheel. To reverse the direction of movement of the wheel slide, theoperator may shift the lever 50 to a position 50b (Fig. 1) therebymoving the pistons 26 and,2.7 into the positions 261) and 27b (Fig. 2).In this position of the valve, fluid entering through the inlet pipe 30into the valve chamber 31 passes through the pipe 39 into the cylinderchamber 34 to force the piston 21 toward the right as viewed in Fig. 1and thereby removes the grinliing wheel from operative contact with thewor One of the objects of this invention is to produce a stepped seriesof uniform feeds of the grinding wheel. To this end, mechanism isprovided which operates in timed relation with the movement of thegrinding wheel slide 12 to move the throttle valve piston 36 andpartially close the V-shaped port 42 at predetermined intervals in theforward feeding movement of the grinding wheel, -,thereby producingsuccessively slower wheel feeding movements. This may comprise anadjustable stop, and preferably a series of stops, arranged inthe pathof a part of the throttling device, such as the valve stem 38. The stopsare moved successively out of the path of the valve stem when the tablehas reached predetermined locations and so permits the throttling valveto be moved successively to definite positions relative to the port 42and thereby control the flow of fluid in the table actuating system. Asimple means for actuating the stops comprises triggers which aresuccessively moved by the moving piston rod 22 and these in turn movethe stops away from the path of the valve stem 38.

As illustrated, this mechanism may comprise a lever arranged to rockabout a vertical stud 61 secured to the base of the machine. The forwardend of the piston rod 22 is provided with a head 62 adapted to contactwith the end of an adjustable screw 63 which permits the operator tovary the point at which the head 62 will operate to swing the lever 60.The other end of the lever 60 is provided with an enlarged portion 64having the adjusting screws 65, 66 and 6'? passing therethrough andarranged to contact with the projections 68, 69 and 70 of the levers 71,'72 and '73 which are pivotally supported on the vertical stud '74.These levers '71, '72 and '73 are diagrammatically illustrated in Fig. land are shown in detail in Figs. 4, 5 and 6. The other ends of thelevers '71, '72 and '73 are provided with the adjustable stops '15, 76and 7'? which are mounted on the ends of the rods '78, '79 and 80. Therods '78,

'79 and 80 pass through the ends of the levers '71, j

'72 and '73 respectively and are provided with the adjustable nuts 81,82 and 83 which are screw threaded on rods '78, 79 and 80 respectivelyso that the operator may readily adjust the position of the stops 75, 76and 77 relative to their supporting levers 71, 72 and 73. The stops arethus arrangdd to be moved out of the path of the member 85 mounted onthe outer end of the valve stem 38 by the trigger mechanism comprisingthe swinging levers operated by the piston rod 22. The valve 36 isnormally biased to a closed position by means of a spring 86 surroundingthe valve stem 38 and interposed between the piston 36 and the valvehead. The tension of the spring 86 tends to move the valve piston 36toward the right, as viewed in Fig. 1, thereby holding the member 85 incontact with the surface of one of the stop pins 75, 76 or 77.

It will be readily seen that when the head 62 on the piston rod 22contacts with the' screw 63 and rocks the lever 60, the screw 65 willcontact with the portion 68 of the lever 71 and swihg it into theposition shown in Fig. 5, thereby withdrawing the stop 75 from itsposition in contact with the member 85. Then the released tension of thespring 86 forces the valve piston 36 toward the right to partially closethe V-port 42. This movement continues until the member 85 contacts withthe second stop 76 which is suitably located to give the desiredthrottling position to the valve 36.- This operates to give a. slowerbut uniform feeding movement to the grinding wheel. In this particularcase, the rapid approaching movement of the grinding wheel is reduced toa grinding feed suitable for grinding the cheeks or side faces of thework piece. 'This slower but uniform rate of feed continues until theadjusting screw 66 contacts with the portion 69 of the lever 72 andswings the lever and thereby withdraws the stop 76 from engagement withthe member 85, whereupon the throttle valve piston 36 moves to a newpostion and further closes the V-port 42 and produces a still slower butuniform feed to grind the body or cylindrical portion of the work piece.This slower grinding feed continues until the third adjusting screw 67contacts with the portion of the lever 73 and swings the stop 77 out ofcontact with the surface of the member 85 thereby closing the V-port 42entirely and stopping the exhaust of fluid from cylinder chamber 34 andpreventing the feeding movement of the grinding wheel toward the work.This permits the grinding wheel to grind out or finish grind the work.During this iinal or finish grinding period, the operator observes theindicator on the grinding gauge to tell when the work has been properlysized, and he throws the lever 50 from the position illustrated in fulllines in Fig. i into position 50?) thereby reversing the direction offlow of the fluid under pressure in the system and removing the grindingwheel rapidly to 'an inoperative position.

By adjusting the screw 63, the operator may vary the time at which thethrottle valve operates relative to the position of the grinding wheelslide. By manipulation of the adjusting screws 65, 66

, and 67, the operator may adjust the time at which each stop 75, 76 and'77 is tripped relative to the movement of the slide 12; and bymanipulation of the nuts 81, 82 and 88 the operator may adjust theposition of the stops 75, '76 and 77 relative to levers 71, 72 and 73 soas to vary the amount of movement of the throttle valve piston 36 foreach successive step in the feeding movement.

In the use of this type of mechanism, it is necessary to reset thethrottle valve 36 after a grinding operaton has been completed before itis in condition for the starting of the next grind ng operation. Toaccomplish this, a piston- 90 is provided as an integral part of thepiston ily apparent from the foregoing disclosure.

27. This piston 90 has a passage 91 (Fig. 2) ex'- tending longitudinallyof the portion 92 and having and outlet 93 which moves into or out ofalignment with the port 94 in the valve casing 25 when the valve ismoved. When the lever 50 is moved into position 50?) thereby moving thevalve pistons 26 and 27 into the positions 26b and 27b, as shown in Fig.2, to admit fluid through the pipe 39 to cause a rearward movement oi.the grinding wheel, fluid is also forced through the passage 91, outlet93, port 94 and through pipe 95 to the chamber 96 in the rear end of thethrottle valve 35. This fluid under pressure operates against the valvepiston 37 to move the pistons 37 and 36 toward the left, as viewed inFig. 1, to bring the valve and its locking member 85 to their initialpositions, as shown in Figs. 1 and 4. A port 97 is prov ded in the valve25 to permit fluid to exhaust from the chamber 96 when the valve piston37 moves rearwardly. The port 97 is connected by a pipe 98 to theexhaust pipe 45. When the reversing valve is in the position shown inFig. 1, fiu'd may exhaust from valve chamber 96, through pipe 95, valvechamber 99, port 97, pipe 98 and into the main exhaust pipe 45.

When the wheel slide 12 travels rearwardly and the head 62 moves awayfrom the adjusting screw 63, it is desirable that the stops 75, 76 and77 be swung back into their normal operating positions in the path ofthe member 85. To accomplish th's, a construction such as that shown inFig. 6 is employed. The stop rod 78 is provided with an enlarged portion100 sliding with'n an opening in the lever '11. con cal collar 101 isslidably mounted on rod 78 and contacts with a projection 102 in thecutout portion 163 of the fixed stud 7a. A spring 104 surrounds the rod78 and is interposed between the enlarged portion 100 and the col'ar161. The tension of the spring 10% normally tends to hold the stop andits supporting rod in the operating position so that the stop is in thepath of the member 85. As thescrew 65 contacts with the portion 68 ofthe lever '71, the lever is thereby swung relative to the fixed stud 74and causes the member 100 to approach the collar 101 thereby compressngthe spring 104. .l/Vhen the grinding wheel recedes the released tensionof the spring 10% operates to swing the lever 71 and the stop 75 backinto the normal operating position as shown in Figs. 1, i and 6. Similarmechanisms for controling the movement of each of the other levers 72and 73 are employed.

It will be readily apparent from this construction, that when the fluidunder pressure is admitted to the valve chamber 96, the pistons 36 and37 will move towards the left as viewed in Fig. 1, thereby forcing themember 85 over the ends of the stops 77, 76 and 75 which spring outwardand then swing behind the member 85 into their normal positions. Thisarrangement automatically sets the throttling valve in its initialstarting position as the grinding whee. is moved rearwardly so that themechanism is ready to start on its forward feeding movement when thegrinding wheel is brought into alignment with the next piece of work.

The operation of this mechan sm will be readwill also be seen thatvarious modifications of the mechanism may be made within the scope ofmy invention as covered by the appended claims.

Having thusv described this invention, what is A frustoclaimed as newand desired to secure by Letters Patent is:

1. A grinding machine comprising a grinding wheel slide, a rotatablegrinding wheel on said slide, a fluid pressure mechanism connected tomove said slide, a fluid pressure system including a throttling valve toconvey fluid to said mechaniim, means tending to bias the valve to aclosed position, a member movable with the valve, and a plurality ofadjustable stops actuated by movement of the slide which successivelyengage said member to position the throttling valve and thereby causethe fluid to flow at successively different rates.

2. A grinding machine comprising a grinding wheel slide, a rotatablegrinding wheel on said slide, a piston and cylinder connected to feedsaid grinding wheel rapidly towards the work, a fluid pressure systemincluding a reversing valve to conduct fluid under pressure to and fromsaid cylinder, a throttle valve mechanism in said system, means actuatedby movement of said grinding wheel slide to position said throttle valvein a predetermined position depending on the position of the slide todiminish the flow of fluid when the slide has reached a predeterminedposition and cause the slide to move thereafterat 'a uniform but slowerrate, and means to adjust the position of the slide at which saidthrottle valve is operated.

3. A grinding machine comprising a base, a grinding wheel slide, arotatable grinding wheel on said slide, a fluid pressure mechanismincluding a cylinder and piston connected to feed said grinding wheeltowards the work axis, a fluid pressure system including a reversingvalve to admit fluid to either end of said cylinder, a throttling valvein said system, means actuated by movement of said slide to operate saidthrottle valve to change the fluid flow when the grinding wheel hasreached a predetermined position and thereby cause the grinding wheel tofeed at a diflerent but uniform rate, means to adjust the time at whichsaid throttling valve operates relative to the grinding wheel movement,and means to adjust said throttling valve to vary the rate of the fluidflow and the grinding wheel movement.

4. A grinding machine comprising a grinding wheel slide, a rotatablegrinding wheel thereon, a cylinder and piston arranged to move saidslide to feed the grinding wheel towards the work axis, a fluid pressuresystem for conveying fluid under pressure to and from said cylinder, areversing valve interposed in said system, a manual control for saidvalve arranged to admit fluid to either end of said cylinder, a throttlevalve interposed in said system to control the exhaust of fluid fromsaid cylinder to regulate the feeding movement of the grinding wheeltowards the work axis, adjustable means actuated by movement of saidgrinding wheel to partially close said throttle valve and produce aslower but uniform rate of movement of said grinding wheel at apredetermined point, and means to adjust the extent of movement of saidthrottle valve to regulate the rate of feed of the grinding wheel.

5. A grinding machine comprising a grinding wheel slide, a rotatablegrinding wheel thereon, a cylinder and piston operatively connected tomove the slide, a fluid pressure system for conveying fluid to and fromsaid cylinder, a reversing valve interposed in said system, a manuallyoperable control for said valve arranged to admit fluid to either end ofsaid cylinder, a throttle valve in said system arranged to control theexhaust of fluid from said cylinder which is normally biased to a closedposition, a trigger mechanism arrangedto normally hold said throttlevalve open, adjustable means actuated by movement of said slide to tripsaid trigger mechanism at apredetermined point to permit the throttlevalve to partially close and thereby reduce the speed of the slide to aslower but uniform rate when the slide reaches a predetermined position,and adjustable means to control the extent of movement of said throttlevalve.

6. A grinding machine comprising a grinding wheel slide, a grindingwheel rotatably mounted thereon, a cylinder and piston arranged to movesaid slide in either direction, a fluid pressure system for conveyingfluid under pressure to said cylinder, a manually operable reversingvalve in said system arranged to control the direction of flow of fluidto either end of said cylinder, a throttle valve in said system tocontrol the exhaust of fluid from one end of said cylinder which isnormally biased to a closed position, a plurality of triggers arrangedto hold said throttle valve open, and means actuated by the movement ofsaid slide to successively trip said triggers to partially close saidthrottle valve when said slide reaches predetermined positions toproduce a stepped series of uniform speeds of the wheel slide.

'7. A grinding machine comprising a grinding wheel slide, a rotatablegrinding wheel therefor, a cylinder and piston operatively connected tomove the slide, a fluid pressure system for conveying fluid to eitherend of said cylinder, a reversing valve in said system arranged tocontrol the direction of flow of fluid to said cylinder, a throttlevalve in said system arranged to control the exhaust of fluid from oneend of said cylinder, a trigger mechanism arranged to normally hold saidthrottle valve open, adjustable means actuated by movement of said slideto trip said trigger mechanism when the slide reaches a predeterminedposition, and fluid connections between said reversing valve and saidthrottle valve to return said throttle valve to its initial positionwhen the reversing valve is changed to move the slide rearwardly, sothat the throttle valve is in proper position for starting the nextgrinding operation.

8. A grinding machine comprising a wheel slide, a rotatable grindingwheel on said slide, a fluid pressure mechanism including a piston andcylinder one of which is connected to feed the grinding wheel towardsthe work axis, a fluid pressure system including a reversing valve toconduct fluid to either end of said cylinder to cause a rapidapproaching or receding of the grinding wheel relative to the work axis,a throttle valve mechanism in said system and means operated in timedrelation with the wheel movement to actuate said throttle valve when thegrinding wheel has reached a predetermined position and cause a slowerbut uniform feed of the grinding wheel into the work to size the same.

9. A grinding machine comprising a wheel slide,- a rotatable grindingwheel on said slide, a

fluid pressure mechanism connected to feed the grinding wheel towardsthe work axis, a fluid pressure system including a valve to conductfluid to said mechanism and cause a rapid approach of the grinding wheeltowards the work axis, means j operated in timed relation with the wheelmovement to actuate said valve when the grinding wheel has reached apredetermined position and cause a slower but uniform feed of thegrinding wheel into the work to rough grind the grinding wheel towardsthe work axis, a fluid pressure system including a valve to conductfluid to said mechanism and cause a rapid approach of the grinding wheeltowards the work axis, means operated in timed relation with the wheelmovement to actuate said valve when the grinding wheel has reached apredetermined position and cause a slower but uniform feed of thegrinding wheel into the work to rough grind the work,

a second means operated in timed relation with the wheel movement toactuate said valve and cause a still slower but uniform feed of thegrinding wheel to finish grind the work and a third t means operated intimed relation with the wheel movement to close said valve and stop thewheel feeding movement.

11. A grinding machine comprising a wheel slide, a. rotatable grindingwheel on said slide, a fluid pressure mechanism connected to feed thegrinding wheel towards the work axis, a fluid pressure. systemincludinga valve to conduct fluid to said mechanism and cause a rapid approach ofthe grinding wheel towards the work axis, means operated in timedrelation with the wheel movement to actuate said valve when the grindingwheel has reached a predetermined position and cause a slower butuniform feed of the grinding wheel into the work to size the same, and asecond means operated in timed relation with the wheel movement to closesaid valve and stop the feeding movement of the grinding wheel.

